Aerosol inhalation devices are used in medical facilities in diagnostic and therapeutic procedures. Such devices are especially useful in pulmonary therapy for pneumonia and for introducing agents such as radioactive vapors for diagnosing diseases. With the advent of new treatments such as gene therapies, there are likely to be increased needs for aerosol inhalation devices that can effectively deliver medicaments to patients.
Aerosol inhalation devices include aerosol-generating equipment, and a means for delivering aerosol to a patient. An example of equipment for generating an aerosol from quid generally is a nebulizer, a device that mixes pressurized air or oxygen with diagnostic or therapeutic materials to create an aerosol. During generation of a liquid aerosol, a liquid to be aerosolized is placed in a reservoir in the nebulizer. Gas such as pressurized air or oxygen enters the nebulizer and acts to draw the liquid up through a delivery tube to an aerosol exit orifice, similar to the operation of a jet pump. At the aerosol exit orifice, the liquid is atomized into a mist referred to as an "aerosol". In some devices, larger drops that are produced in the mist impinge on baffles above the aerosol exit orifice where they drain back into the reservoir of the nebulizer. Smaller drops are entrained by the gas and are carried through the delivery system to the patient's lungs. Nebulizers are disclosed in U.S. Pat. Nos. 4,823,784 and 5,630,409, the disclosures of which are hereby incorporated herein by reference in their entirety.
Since most aerosol inhalation devices are currently made for a single use and are thereafter disposed, any medication or diagnostic material remaining in a device becomes waste. In addition, the greater the volume of the device, the lower the efficiency of delivery of aerosol to a patient, and the greater the air or oxygen pressure that can be required to deliver the aerosol. Valves within the path of aerosol delivery can further decrease efficiency by interrupting the flow of aerosol, affecting the pressure of the gas entering the device, and/or entrapping aerosol particles.
There have been few improvements directly related to efficiency of delivery and reduction of waste. In view of these and other recognized deficiencies of current devices, a need remains for improved aerosol delivery devices.